Monitoring the brain

The nervous system can be easily evaluated in the awake patient by neurological physical examination and laboratory tests. This is no longer possible when the patient is unconscious, because of general anaesthesia or the presence of central nervous system pathology. Neurological monitoring in such conditions relies on the use of diagnostic tests previously used in the laboratory, and the main indications for neuromonitoring are the prevention of ischaemic damage and/or mechanical injuries to the brain or the spinal cord. The usefulness of neuromonitoring in preventing neurological complications relies on its ability to detect neurological dysfunction at a reversible stage. This chapter provides an overview of the most-used nervous system monitors, divided into monitors that assess the function of the nervous system, monitors that evaluate cerebral haemodynamics and monitors that assess cerebral oxygenation.